Stain preventing shortstop bath for photographic azine dye images



Patented 'Nov. 18, 1952 STAIN PREVENTING SHORTSTOP BATH FOB PHOTOGRAPHIC AZINE DYE IMAGES Robert C. Gunther, Galesburg, Ill., and Vsevolod Tulagin, Phillipsburg, N. J assignors to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application March 21, 1950, Serial No. 151,051

6 Claims.

This invention relates to photographic shortstop baths for removing color developer stains from phenazonium (azine) dyestuff images following color forming development with 2,4-diamino-aniline developing agents.

There is described in United States Patent 2,486,440, issued November 1, 1949, a method of producing azine dyestuff images by color developing silver halide emulsions with a 2,4-diaminoaniline in the presence of a color former.

The azine dyes produced in this way have unusual stability and superior pectral characteristics, particularly when compared with the quinonimine or azomethine dyes produced with developers of the p-phenylenediamine type.

Despite the many recognized advantages of this new class of color developers, they possess one disadvantage which provides a somewhat serious problem in the use of the azine method. This disadvantage occurs in the developement of multilayer film and is manifested, especially when the aromatic triamino developing solution is old and badly oxidized by leaving a developer stain in the processed film. This stain, in most cases, is quite substantive to gelatin and can usually be completely removed only by excessively long wash times after color development. This developer stain may be observed particularly in' the highlights or Whites of the processed film. In the color developed areas of the film, it-produces a serious loss in color rendition. Furthermore, such a stain may contribute. in. no small degree to the loss of storage stability of the final color image, including both the so-called 1ight and dark fading characteristics.

The stain originating from. oxidation of the developer substance either in the solid state or in solution is not to be confused with stain that may be formed imagewise during the color development. In the former case, the developer substance is oxidized by air, probably to some sort of a dye, and this dye is adsorbed to the gelatin in a more or less random, over-all pattern. In the latter case, oxidized developer of a species different than that originating from aerial oxidation is formed by reduction of the positive silver halide image by the color developer. This transient oxidized developer form has recourse to at least two of severa1 reactions: (1) to couple with a color former taproduce an azine dye, or (2) ta couple with another molecule of oxidized developer to produce a stain. In the case of stain arising from aerial oxidation of the developer, it was found that it could be removed almost completely if the film were washed sufficiently after color development. On the other hand, stain produced in situ during the color development step cannot be removed or destroyed any more than the dyes themselves may be removed or destroyed. stain produced by aerial oxidation of the developer is a function of the general type of developing agent being used, whereas stain produced during color development is a function of the particular type of a developer being used. This is best exemplified in the case of the N- substituted ZA-diamino-anilines used in the formation of azine dyestuffs. The 2,4-diaminoanilines, as a general class, are oxidized quite readily by air since they contain an additional amino group to the two present in the already unstable diamino-benzene type developers used in the formation of azomethine dyestufis. On the other hand, within this general class of azine dye forming color developers, there are particular developers which do not produce imagewise stain,

and there are other developers which do produce stain in the color development step.

It is known that developing, washing, and fixing baths, containing pyruvic acid, its ammonium or alkali metal salt, have been suggested by the art for the elimination of color stain in photographic silver halide emulsion layers containing q'uinonimine or azomethine dye images obtained by color forming development with primary aromatic amino developing agents. The pH of the treating bath must be alkaline or at least above the pH of 5, otherwise the azomethine link in the dyestuff image is cleaved. In other words, the azomethine dye image is discharged when the pyruvic acid treating bath is acid, i. e., of a pH of 2 to 4. In order to be effective, the pyruvic acid treating bath must contain a buffering agent to reduce the acidity and raise the pH from 5 to at least 8.

When a pyruvic acid shortstop bath of a pH of 5 to 8 is employed in the processing of multicolor film by the azine method while using 2,4- diamino-anilines for color development, the stain arising from aerial oxidation of the color developer is not diminished or eliminated.

Shortstop baths consisting of aqueous solutions of mineral acids or short chain aliphatic mono-, di-, and tribasic acids are also ineffective since they precipitate the ZA-diamino-aniline color developers and lead to a product of extremely poor color rendition.

It is an object of the present invention to provide a simple and economical method of eliminating color stain from phenazonium dyestuif images obtained by color forming development With 2,4-diamino-aniline developing agents.

Other objects and advantages will become apparent from the following description.

We have now found that stains arising from aerial oxidation of ZA-diamino-aniline developing agents in the color forming development of azine dyestuif images are readily eliminated by treating a multilayer color film, after colorforming development, with an aqueous shortstop bath containing from 0.5 to of a pyruvic acid.

Best results are obtained when the concentration.

of such acid is in the range of 3 to 5%.

The shortstop bath may be used with any N- substituted 2,4-diamino-ani1ine developer, especially those in which the nitrogen atom in the 2-position bears an aliphatically bound hydrophylic group. Developers of this type produce a minimum of imagewise stain formed during color development. The bath may be used after the color development of either a monolayer or a multilayer. It is equally efiective as a shortstop after color development, whether it be the development of an emulsion containing a nondiffusing color former or the development by diffusion of a silver halide emulsion by a developer solution containing the color former. The bath is also equally efiective after either: reversal or negative color development.

When using the preferred concentration of 3 to 5%, the shortstop bath has a pH ranging from 2 to 4. At this pH, the pyruvic acid neutralizes the developing media and stops further development.

The most unusual feature of the present invention is that while the pyruvic acids neutralize the developing media and stop further development, they do not precipitate the 2,,4-diaminoaniline developing agent as is the case with min.- eral and short chain aliphatic mono-, di-, and tribasic acids. It is believed that this unusual property is attributable to the pyruvic acids or their degradation product, such as acetaldehyde (formed by the loss of CO2) which readily reacts with the 2,4-diamino-ani1ine developing agent or its reaction product to give a water soluble product.

Any pyruvic acid may be used for our purpose, i. e.,v pyruvic acid itself, or a-substituted derivatives thereof. These compounds may be exemplified by the following general formula:

ACOCOOH wherein the a-substituent represented by A is either, an alkyl, e. g., methyl, ethyl, propyl, isopropyl, butyl, etc., monoor di-(carboxy) methyl, alkylketomethyl, e. g., acetonyl, ethylketomethyl, butylketomethyl, etc., monoor di-(acetyD- methyl arylketomethyl, e. g., phenacyl, p-tolylketomethyl, m-xylketomethyl, etc., p-alkylethenyl, e. g., propenyl, isopropenyl, 1- or 2- methylpropenyl, 2-, or 3-butenyl, 3-methyl-1- butenyl, l-pentenyl, etc., fl-arylethenyl, e. g., styryl, methylstyryl, etc., or a Z-keto-saturated carbocyclic or N-heterocyclic radical having a 6-membered ring including at least 5 carbon 4 atoms, e. g., 2-cyclohexanonyl, methyl-Z-cyclohexanonyl, 3-(a-piperidonyl), etc.

The pyruvic acids may be further characterized by the following general formulae:

( n-omcocoou onooooon 3) R2=CUC0COOH 4) o ll ,0 l

oncoooon wherein R represents either hydrogen or an alkyl group, e. g;, methyl, ethyl, propyl, isopropyl, butyl, etc., or acyl group, e. g., acetyl, pr-opionyl, butyryl, a-toluyl, 0-, m-, or p-toluyl, curnoyl, etc., each of the Ris represents either carboxy or acetyl, R2 represents an alkylidene or arylidene group, e. g., ethylidene, propylidene, isopropylidene, butylidene, isobutylidene, benzylidene, p-methylbenzylidene, cinnamylidene, cuminylidene, etc., and Z represents the atoms necessary to complete a cyclohexanonyl or piperidinyl ring.

The following compounds are illustrative of the pyruvic acids contemplated by the present invention:

(1) CHsCOCOOH Pyruvic acid (2) CHaCHzCOCOOH 3-methyl-pyruvic acid (3,) CHaCOCHzCOCOOH Acctyl-pyruvic acid (4) CsHaCOCHzCOCOOH Bcnzoyl-pyruvic acid (5) p-CHsCsHsCOCI-IzCOCUOI-I' p-Toluyl-pyruvic acid (6) CH3CH=CHCOCOOH Methylmetliinyl-pyruvic acid (7) CsI-I5CH=CHCOCOOH Phenylmetllinyl-pyruvic acid (8) GH;-CHGH=CHCQOOQI lifi-diacctyL-Ilyruvic acid 9) H o o 0 CH0 0 C O OH HO O C B,B diCarh0Xy-pyruvic acid (10) CHaC O CH C 0 C O 0H CHaC O IsopropylmethinyLpyruvic acidv CHCOCOOH C H COCOOH H 4-0xo-3-piperidineglyoxylic acid carried into the bath by the color developed film.

The following compositions are illustrative of the shortstop baths with or without buffering agents which have a pH ranging from 2 to 4:

(1) Pyruvic acid grams 3O Water to make cc- 1000 (2) 2-oxo-cyclohexaneglyoxylic acid grams .Water to make cc 1000 (3) Pyruvic acid grams 50 Potassium alum do Water to make cc 1000 (4) 5,;8-dicarboxy-pyruvic acid grams Water to make cc 1000 (5) Methylmethinyl-pyruvic acid grams Sodium sulfate do 60 Water to make cc 1000 (6) Benzoyl-pyruvic acid grams 15 Water to make cc 1000 (7) Methyl-pyruvic acid grams Potassium alum "do.. 10 Water to make cc 1000 (8) dfi-diacetyl-pyruvic acid grams 5 Water to make cc 1000 The 2,4-diamino-anilines which are utilized as the color developers for the production of azine dyestuff images are of the type described in the aforementioned Patent No. 2,486,440 and in application Serial No. 101,913, filed June 28, 1949, and entitled Color Developers for the Production of Azine Dye Images.

Specific examples of such developing agents are:. i

4 (B hydroxyethylamino) 6 (4 carboxymethoxy-phenylamino) -metanilic acid 4- (carboxymethylamino) -6- 4 -methoxy-phenylamino) -metanilic acid 2- (B-sulfoethylamino) -4-phenylamino aniline 4,6-di(B-hydroxyethylamino) -metani1ic acid 4 (fi-hydroxyethylamino) 6 phenylaminometanilic acid 2 (B hydroxyethylamino) 4 (5-sulfoethylamino) -5-methyl aniline 4-(e-hydroxy-fi-methyl ethylamino) -6-phenylamino-metanilic acid 4 [0. di(hydroxyethyl)ethylamino] 6 (3'- ethoxy-phenylamino) -metanilic acid 4 (s hydroxyethylamino) 6 methylaminometanilic acid 4 (sulfomethylamino) -6- (methylphenylamino) metanilic acid 4 (B hydroxyethylamino) 6 methylaminometanilic acid Color formers which are used with the aforementioned developers to give yellow azine dye images are also described in the aforementioned application Serial No. 101,913. These com- 6 pounds aretypified by the fact that they are open chain ketomethylene compounds. Examples of such compounds are:

Acetoacetanilide N-l-naphthylacetoacetamide N,N'-ethylenebisacetoacetamide DJ '-Bi-o-acetoacetaniside N-2-naphthaylbenzoylacetamide p,p'-Bi-acetoacetanilide a,a' Terephthaloylbis-(3-ch10ro-4,6-dimethoxyacetanilide) a-Benzoylacetanilide Preferably, the color formers utilized contain a group rendering them non-migratory in the emulsion. Examples of such compounds are:

2-(m-benzoylacetamidophenyl) 1 octadecyl-5- benzimidazolesulfonic acid 3,3 ureylenebis 5 p benzoylacetamidobenzamide-benzenesulfonic acid 2-p benzoylacetamidobenzamido 6 stearoylamino-p-toluenesulfonic acid 2 (p benzoylacetamidophenyl) 1 octadecyl: 5-benzimidazolesulfonic acid p-Cyanoacetyl-3-octadecenylsuccinalic acid are 6-halogen-S-hydroxy-quinolines, and particularly those which are non-migratory in the emulsions. Examples of the latter type compounds are:

G-stearoylamino- 2 -(2'-phenyl- 6-bromo- 8' hydroxy-cinchoninoyl)-aminotoluene 4 -sulionic acid 2 phenyl- 6 -chloro- 8 -hydroxy-cinchoninoyloctadecyl taurine 6 decoxy 3 (2 phenyl 6 bromo 8 hydroxy-cinchoninoyl) amino-benzenesulfonic acid 2 (3 stearoylaminophenyl) 6 bromo 8 hydroxy-cinchoninic acid 2 stearoylamino 6 (6 chloro 8 hydroxycinchoninoyl) -aminotoluene 4 sulfonic acid, and the like.

Color formers for the cyan image are also described in application Serial No.-101,913, now Patent No. 2,570,116, dated October 2, 1951, and in United States Patent 2,445,252, issued July 13, 1948. Preferably, these color formers are aryl-J- acid derivatives, particularly those containing a group rendering the color former non-migratory in the emulsion. Examples of the latter compounds are:

Dodecyl urethane of fi-sulfoethyl-J-acid Tetradecyl urethane of p-anisyl-J-acid 2-hexadecyl urethane of phenyl-J-acid 4-stearoylaminophenyl-J-acid, and the like The following examples serve to illustrate the invention, but it is to be understood that the invention is not restricted thereto.

Example I A photographic silver bromide emulsion was exposed, the latent image developed in a black silver halide developed for 10 minutes in a solution of the following composition:

Sodium carbonate, monohydrate g rams 40 Sodium sulfite do 40 Ethylenediamine do 15 8-Hydroxyquinoline do 3 4- (p-hydroxyethylamino) -6-phenylamino-metanilic acid do 5 Water to make cc 1000 After development, the film was rinsed and treated for 3 minutes in a bath of the following composition:

3-(2-cyclohexanonyl) -pyruvic acid grams" 30 Water to make cc 1000 The film was then washed, bleached in ferricyanide bleach and fixed in an acid hardening hypo solution. There is thus obtained a brilliant magenta azine dyestufi free from stain.

Example II An integral tripack with a bottom layer composed of a red-sensitive emulsion containing phenyl-J-acid-N-octadecyl urethane; a middle layer composed of a green-sensitive emulsion containing 2 stearoylamino 6 (8 hydroxycinchoninoylamino) -toluene-4-sulfonic acid, and a top layer composed of a blue-sensitive emulsion containing 2 (4 benzoylacetaminophenyl) 1 octadecyl-5-benzimidazolesulfonic acid was exposed and the latent image developed in a black and White developer, re-exposed, and the residual silver halide developed in a solution of the following composition:

Sodium carbonate, monohydrate grams 40 Sodium sulfite do 60 Potassium bromide do- 5 Pyridine do 16 Benzylamine do 1 4- (p-hydroxyethylamino) -6-phenylamino-metanilic acid do 5 Water to make cc 1000 After color development, the film was rinsed and treated for 5 minutes in a bath of the following composition:

Pyruvic acid "grams-.- 50 Potassium alum do 15 Water to make cc 1000 v The filmwas washed, bleached in a ferricyanide bleach and fixed in an acid hardening solution. There was obtained a multicolor, stain-free positive dye image.

Example II I An integral tripack of essentially the same composition as used in Example II was exposed and color developed for 15 minutes to a negative image in a solution of the following composition:

Trisodium phosphate grams 40 Sodium sulfite do 40 Potassium bromide do 12.5 Hydroxylamino hydrochloride do 1 4- (fl-hydroxyethylamino) -6-benzylamino-metanilic acid do 6 Water to make cc 1000 After development, the film was rinsed and treated for 5 minutes in a bath of the following composition:

Methylmethinyl-pyruvic acid grams 40 Sodium sulfate do Water to make cc 1000 The film was washed, bleached in ferricyanide bleach, and fixed in an acid hardening hypo. There was obtained a brilliant, multicolor negative dye image, completely free from stain.

We claim:

1. In the process of producing subtractivly colored azine dye images in a silver halide emulsion layer containing a. color former capable of coupling with the oxidation products of a 2,4 diaminoaniline developing agent to form an azine dye which comprises exposing the emulsion and developing the same with a color developer containing as the effective developing agent a 2,4- diamino-aniline, the improvement which comprises avoiding the formation of stain after the color development by shortstopping the color developed emulsion with an aqueous bath having a pH ranging from 2 to 4 and containing an organic acid of the class consisting of pyruvic acid and its p-acyl, fl-alkyl, s-aryl, and p-carboxy-substituted derivatives.

2. In a process according to claim 1, wherein the acid is pyruvic acid.

3. In a process according to claim 1, wherein the acid is 2-oxo-cyclohexaneglyoxylic acid.

4. In a process according to claim 1, wherein the acid is methylmethinyl-pyruvic acid.

5. In a process according to claim 1, wherein the acid is methyl-pyruvic acid.

6. In a process according to claim 1, wherein the acid is flLfi-dicarboxy-pyruvic acid.

ROBERT C. GUNTHER. VSEVOLOD TULAGIN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

1. IN THE PROCESS OF PRODUCING SUBSTRACTIVLY COLORED AZINE DYE IMAGES IN A SILVER HALIDE EMULSION LAYER CONTAINING A COLOR FORMER CAPABLE OF COUPLING WITH THE OXIDATION PRODUCTS OF A 2,4 DIAMINOANILINE DEVELOPING AGENT, TO FORM AN AZINE DYE WHICH COMPRISES EXPOSING THE EMULSION AND DEVELOPING THE SAME WITH A COLOR DEVELOPER CONTAINING AS THE EFFECTIVE DEVELOPING AGENT A 2,4DIAMINO-ANILINE, THE IMPROVEMENT WHICH COMPRISES AVOIDING THE FORMATION OF STAIN AFTER THE COLOR DEVELOPMENT BY SHORTSTOPPING THE COLOR DEVELOPED EMULSION WITH AN AQUEOUS BATH HAVING A PH RANGING FROM 2 TO 4 AND CONTAINING AN ORGANIC ACID OF THE CLASS CONSISTING OF PYRUVIC ACID AND ITS B-ACYL, B-ALKYL, B-ARYL, AND B-CARBOXY-SUBSTITUTED DERIVATIVES. 